1. Field of the Invention
The present invention relates to a recording tape cartridge that singly houses, inside a case, a reel onto which is wound recording tape such as magnetic tape used as a recording and playback medium mainly for computers and the like.
2. Description of the Related Art
Conventionally, recording tape cartridges have been known where recording tape such as magnetic tape used as a data recording and playback medium for computers and the like is wound onto a reel and the reel is singly housed inside a case configured by an upper case and a lower case. A leader member that a pullout member of a drive device pulls out is fixedly attached to the distal end of the recording tape. As an example of the leader member, there is a substantially dumbbell-shaped leader pin disposed with flange portions on both end of a body portion to which the recording tape is fixedly attached directly or via leader tape.
The leader pin is held, such that its axial direction is in the height direction of the case, as a result of the flange portions being housed in concave holding portions formed in the upper case and the lower case in the vicinity of an opening and the flange portions being held by a spring or the like. Consequently, when shock is imparted to the vicinity of the opening as a result of the recording tape cartridge being dropped or the like and the upper case and the lower case flexurally deform (split) so as to move apart from each other, there has been the potential for the flange portion to come out of the holding portions and for the leader pin to slant and fall out of the holding portions.
When such a phenomenon occurs, a problem arises in that the pullout member of the drive device becomes unable to check the leader pin, which leads to a system error. For that reason, a recording tape cartridge has conventionally been proposed where undercut grooves in which the flange portions of the leader pin lock—that is, concave grooves that the flange portions enter—are formed in the holding portions so that the flange portions of the leader pin are prevented from coming out of the holding portions (e.g., see Japanese Patent Application Publication No. 2001-148179).
However, such undercut grooves have the problem that it is necessary for them to be molded by disposing a slide mechanism in the mold, so the configuration of the mold becomes complicated and the mold becomes expensive. Further, there is also the problem that, because the shape in the vicinity of the holding portions is complex, it becomes difficult to stabilize the shape and it becomes easier for trouble to occur when the undercut grooves are molded by disposing a slide mechanism in the mold.